Arturo malignant



(No Model.) 7

A. MALIGNANI.

'PROGESS 0F EVAGUATING INGANDES'GENT LAMPS. No. 537,693. Patented Apr.16, 1895.

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fwd/b4 UNITED, STATES PATENT OFFICE.

ARTURO MALIGNANI, OF UDINE, ITALY.

PRQGESS OF EVACUATINGi INCAN'DE'SCENT LAMPS.

SPEGIFIGATION fOrming part of Letters Patent No. 537,693, dated April16,1895. Application filedAugust M'h 1894. Serial No. 5205395. (Nospecimens.) Patented in ItalyJ'anuary 7, 1894, XXVIII,'3,550, LXX,

46; in Austria March 16, 1894, No. 44,486;

1'0 all whom it may concern:

Be it known that I, ARTURO MALIGNANI, a subject of the King of Italy,and a resident of Udine, in the Kingdom of Italy, have invented acertain new and useful Improved Process for Evacuating IncandescentLamps, of which the following is a full, clear, and exactdescriptiou,and for which I have obtained a patent in Italy, datedJanuary 7, 1894, Vol. XXVIII, No. 3,550, Att. LXX, No.46; in Belgium,dated July 16, 1894, No. 110,854; in Austria, dated March 16, 1894, Reg.44, Fol. 486, and in Hungary, dated May 5, 1894, No. 354.

The present invention consists of a process for evacuating incandescentlamps and bulbs.

Reference being bad to the accompanying drawing, the bulb A is providedwith a small glass tube '1 for the purpose of extracting the air and thegases therefromas hereinafter spec] tied. Substances, adapted undercertain circumstances to generate gases or vapors,

such as arsenic, sulphuric or iodine are then introduced into theinterior of the bulb A advantageously at about the center of the tube'1. The gases thus generated are intended to combine with the gasesgenerated by the filament of the lamp when brought to incandescence andform aliquid or solid precipitation.

The most convenient method is to dissolve or dilute a powder in or withappropriate liquids, such as alcohol, essence of tremandra or the likein which case the same can be applied most easily. The lamp is thenconnected with a vacuum pump of any kind by means of the. tube '1 andexhausted to the extent of about two millimeters of mercury. The vacuumhaving been obtained, the lower end of the tube is soldered up and thecarbon filament is then brought to intensive incandescence,

which has the effect of generating the gases contalned therein.

During this time the part containing the substance, is heated bysuitable means such as a spirit lamp, or the like, which causes the saidsubstances to be transformed into gases or vapors. These latter thencombine withthe gases and vapors generated by the filamentto form asolid cipitat-ion, so that an almost perfect vacuum is obtained. Theintroduction of a small quantity of ether vapors or otherhydrocarbonates into the lamp renders the combination of the above gasesand vapors easier and more energetic and assists the production of orliquid prethe vacuum. After having'obtained the vacuum it only remainsto solder up the tube T at the lower part b of the bulb so that thelatter can be removed and thelamp is ready for sale.

These operations can be performed very quickly as it is possible toobtain a vacuum in from one to three minutes and even less,

according to the nature of the filament,which varies. The quantity andnature of the gases generated by the filament vary also, so that It isnecessary that the substances, the vapors of which are to beprecipitated in a solid or liquid state, should be carefully chosendueregard being had to the nature of the filament and the proportion shouldbe varied accordingly.

I claim as my invention 1. A process for producing a vacuum in the bulbsof incandescent lamps consisting in first introducinginto a tubularelongation of said bulb suitable substances capable of being gas ifiedby heat and combining with the gases generated by the filament whenbrought to incandescence to form solid or liquid precipitations, thenexhausting the said bulb by means of a pump and sealing the said tubularelongation up, then bringing the filament to intensive incandescence andsimultane-v ously heating the substance in the elongation aforesaid andfinally sealing 0d the said elongation in the manner and for thestantially as described.

2. In a process for producing a vacuum in the bulbs of incandescentlamps consisting in -first introducing into a tubular elongation of Ithe bulb a substance or substances having the qualities specified,exhausting the bulb by means of a pump, sealing the said tubularelongation then bringing the filament to intensive incandescence andsimultaneously heating the said substance or substances in theelongation and sealing oif the said elongation, the application in thebulb of others or other suitable hydrocarbonates during the process inthe manner and for the purpose substantially as described.

In witness whereof-I have hereunto set my hand in presence of twowitnesses.'

ADOLF LINDERMANN, H. ABERT JOHNSON.

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